For many years, slot machines have been a popular attraction at gambling casinos and other gaming establishments. Such slot machines typically have a color display of gaming indicia, such as cherries, plums, oranges, sevens, etc. arrayed in rows and columns across the front of the slot machine. These gaming indicia can be spun into motion for game play by the insertion of a coin into the slot machine and pulling the slot machine handle. During game play, the inserted coin is collected in a coin reservoir within the slot machine called a "shopper." At the end of game play, the inserted coin will be retained in the hopper if there is a losing combination of gaming indicia shown or, alternatively, may be returned from the hopper to the slot machine player, perhaps with additional coins, if there is a winning combination of gaming indicia shown.
Periodically, slot machine hoppers must be serviced by casino technicians. For example, the hopper may have too few or too many coins and must have its contents adjusted appropriately. Also, coins might be jammed in parts of the hopper in such a way that the hopper cannot function properly If so inclined, a dishonest technician can pilfer a few coins each time he services a slot machine. While each individual instance of such pilfering may not represent a significant threat to a casino's bottom line, the cumulative loss over time from such pilfering can be quite large. Casinos have tried to combat this problem by, among other things, assigning two or more technicians to each task requiring a slot machine to be opened. However, this approach leads to additional labor costs and may not even help if each of the assigned technicians is dishonest.
An alternate existing solution is to seal the hopper so that only trusted money-handling employees working in a cashier's cage can get to the coins. Nonetheless, slot machine hoppers are difficult to seal because such hoppers must typically give out coins after a winning play as well as receive them. Having coins jam in the hopper is also an ongoing concern. In those cases where the hopper is prone to jamming, sealing the hopper would inevitably result in greater down-time for the slot machines and create a loss of slot machine use which could be more detrimental to the casino than the theft loss.
Coins can be pilfered from slot machines hoppers not only by casino technicians but also by the slot machine players. For example, a player might attach a string to the coin he is inserting into the slot machine so that he can retrieve the coin from the slot machine by simply pulling the string after the coin has been erroneously counted as "received" by the slot machine and game play has begun. Also, the player might try to jam the payout counter after receiving a winning combination so that the slot machine continues to eject coins well in excess of the amount to which the player is entitled.
Unfortunately, merely counting passing coins as they go into the hopper and counting passing coins as they leave the hopper would not solve these types of theft problems. In the case of player fraud, the player can effectively fool or otherwise disable the existing types of coin counters. Similarly, in the case of technician fraud, such a physical inventory would only indicate that coins are missing, not who took them.
Prior art systems exist to count coins by weighing them. For example, U.S. Pat. No. 5,193,629 issued to Lare and U.S. Pat. No. 4,512,428 issues to Bullivant describe apparatuses for weighing coins. Nonetheless, while such weighing devices might be suitable for weighing coins in a money room, they are unsuitable for weighing coins in a vibration-prone gaming machine environment where the hoppers being weighed must be enclosed to prevent theft by players.